Pneumatic conveying systems are systems used to transport large quantities of particulate material through convey lines (e.g., conduits, ducts, pipes, or the like). Examples of particulate material include powders, granules, pellets, pet foods, snack foods, seeds, beans, nuts, pasta, and the like. In a common pneumatic conveyance system, a fluid, such as air, is blown into the convey lines to cause the particulate material to travel through the convey lines to a receiver. In particular, the air can be introduced to the convey line, under pressure, via a pressure blower. The particulate material can be introduced into the convey line through a rotary-valve airlock, which is positioned downstream from the pressure blower. Under the force of the air flow, the air and particulate material will travel through the convey line to the receiver positioned at an end of the convey line.
After a period of operation, it is generally necessary to clean an interior of the convey line, as residue from the particulate material, as well as other sediment, contamination, or undesirable material can be present in the convey line. Cleaning is particularly necessary when the particulate material being conveyed is a food product, which is highly susceptible to contamination by bacteria or other contaminants. In some instances, the particulate matter can be caked as a residue on the interior wall of the convey lines. Such caking of residue can be particularly difficult to clean and remove from the convey line.
Various systems currently exist for cleaning convey lines. For example, a “pig” in piping system terminology refers to a projectile that has approximately the same diameter as the internal diameter of a convey line. The pig can be forced through the convey line for purpose of removing contamination, sediment and other undesirable matter. This methodology is widely used in industries such as oil and gas and other liquid pumping processes, and many products exist to facilitate the cleaning of such oil and gas pipelines. However, when dealing with dry, particulate material processed via pneumatic convey lines, currently-used systems and methods are less refined. For example, in pneumatic conveyance systems, the convey line must be opened around a joint area so that a pig can be manually inserted into the convey line. Thereafter, the convey line is closed and the pig can be sent down the convey line in a loosely controlled (or uncontrolled) manner by pressurized air flow from the pressure blower. However, such currently-used systems generally do not include specific component to extract the pig from an end of the convey line. As such, the pig will generally exit the convey line into the same receiver in which the particulate material normally flows. Thereafter, the pig must be retrieved manually from the receiver.
In view of the above, there is a need for a system and method for automated cleaning of a pneumatic conveyance system. For instance, there is a need for a system and method whereby a pig can be introduced to a pneumatic conveying system for the purpose of line cleaning, and then extracted from the system without requiring manual intervention (manual intervention refers to opening convey line joints and/or fishing out projectiles from particular matter receivers). Additionally, there is a need for a cleaning system whereby control of the pig as it travels through the convey line is can be substantially automated. Furthermore there is a need for a pig designed to works efficiently with other components of the cleaning system and, more generally, of the pneumatic conveyance system.